Semiconductor devices can be fabricated by covering a main surface of a semiconductor chip and adjacent side faces with an encapsulation material. The contact pads are arranged on the other main surface of the semiconductor chip and can be connected to external contact pads of the semiconductor device by means of a redistribution layer. The packaging of the semiconductor chips by the encapsulation material can be done on a wafer level by means of, for example, the so-called extended wafer level packing in which a plurality of semiconductor chips are arranged on a carrier and the encapsulation material is molded over the semiconductor chips in a molding apparatus. The panel thus produced is also called a reconfigured wafer.
The practice has shown that the currently utilized mold processes and materials may lead to instabilities of the form and shape of the reconfigured wafer. Depending on the process conditions, in particular the temperature, undefined and uncontrolled warpage of the reconfigured wafer may occur. For that reason the molding process is carried out at lower temperatures in order to reduce or avoid the warpage. In case that the planarity of the molded reconfigured wafer is not satisfactory, an additional temperature process has to be performed in order to correct or adjust the warpage. This additional warpage adjust temperature process increases the overall fabrication costs and, moreover, mechanical stress may be incorporated into the reconfigured wafer by this process. This mechanical stress may then decline in succeeding process steps in an uncontrolled manner. On the other hand, when using a reduced mold temperature, a reconfigured wafer may result which is not stably cured or hardened.